The present invention relates to circuitry for controlling an electrophotographic image forming apparatus.
An electrophotographic copier, facsimile machine, laser printer or similar image forming apparatus implemented by electrophotography has high-tension power sources for applying high voltages to, for example, corona dischargers which charge the surface of a photoconductive element for forming an electrostatic latent image representative of an original document on the photoconductive element. It has been customary to maintain the output voltages of such power sources constant. This brings about a problem that, when toner particles and paper dust deposit on any of the corona dischargers, the charge current of the photoconductive element which is charged by the corona discharger is varied to degrade the image quality.